People stand under banners on the front of the New York Stock Exchange that bears a Mothers Day's message from listed company Proctor and Gamble, Friday, May 7, 2010. Proctor and Gamble Co. representatives and recent Winter Olympians are scheduled to ring the exchange closing bell for their Proud Sponsor of Moms program. (AP Photo/Richard Drew)— AP

People stand under banners on the front of the New York Stock Exchange that bears a Mothers Day's message from listed company Proctor and Gamble, Friday, May 7, 2010. Proctor and Gamble Co. representatives and recent Winter Olympians are scheduled to ring the exchange closing bell for their Proud Sponsor of Moms program. (AP Photo/Richard Drew)
/ AP

A man takes a photo of the front of the New York Stock Exchange that bears a Mothers Day's message from listed company Proctor and Gamble, Friday, May 7, 2010. Proctor and Gamble Co. representatives and recent Winter Olympians are scheduled to ring the exchange closing bell for their Proud Sponsor of Moms program. (AP Photo/Richard Drew)— AP

A man takes a photo of the front of the New York Stock Exchange that bears a Mothers Day's message from listed company Proctor and Gamble, Friday, May 7, 2010. Proctor and Gamble Co. representatives and recent Winter Olympians are scheduled to ring the exchange closing bell for their Proud Sponsor of Moms program. (AP Photo/Richard Drew)
/ AP

NEW YORK 
Stocks had another volatile day Friday, swinging widely before closing sharply lower.

The Dow Jones industrials closed with a loss of about 140 points, having been down almost 280 earlier. That followed a brief plunge of nearly 1,000 points on Thursday, the biggest one-day drop in the Dow's history. The erratic trading Friday was no surprise - stocks often fluctuate sharply right after the market suffers a big slide.

Traders were still anxious amid lingering questions about what caused Thursday's sudden drop. Several possibilities were being investigated, but as of late Friday no clear explanation had emerged.

The market looked past a surprisingly strong report on the U.S. jobs market and focused instead on the harrowing plunge the day before and the latest moves in Europe's spreading debt crisis that had helped trigger Thursday's big drop.

Meanwhile, Germany's parliament approved Berlin's share of the rescue package after a boisterous debate. However, investors still fear that Greece may not make a May 19 deadline to make a debt repayment.

The concerns go far beyond Greece, the smallest economy in the European Union. A further loss of confidence in European government debt could have an impact on other weak countries like Portugal, potentially requiring another difficult bailout process. The debt crisis has already badly undermined Europe's shared currency, the euro.

"You're not concerned about the kid with the cold, but how he spreads it to the rest of the class," said Len Blum, a managing partner at investment bank Westwood Capital. Blum noted that Greece's debt problem could be similar to the subprime mortgage meltdown in the U.S., which quickly spread to other parts of the financial system.

According to preliminary calculations, the Dow closed down 139.89, or 1.3 percent, at 10,380.43

Falling stocks outpaced gainers two-to-one on the New York Stock Exchange, where volume was a heavy 2.4 billion shares.

Friday's trading left the Dow down 5.7 percent for the week and erased its gains for the year. The S&P fell about 6.4 percent, while the Nasdaq was off 7.9 percent for the week. The S&P and Nasdaq also went into the red for 2010.

The week's losses would put the market about well toward what experts call a "correction," usually defined as a drop of between 10 percent and 20 percent following a sustained rise. The Dow is now 7.4 percent off its recent high of 11,205.03 reached on April 26. The S&P 500 is down 8.7 percent from its recent high of 1,217.28 reached April 23.

Stocks have been on a nearly uninterrupted upward path since March of last year, when indexes hit 12-year lows. Analysts have been predicting a correction for months, only to see the market bounce back after brief periods of decline.